In ultrasound scans of lymph nodes or breast cancer lesions, it is common practice that the operator moves a handheld ultrasound probe and manually selects images from the resulting video stream for storing. Furthermore, the operator can optionally place graphical annotations or markers on the image in order to identify the position and extent of the structure under investigation.
Staging of axillary lymph nodes is an important step in the assessment of the spread of the disease in newly diagnosed breast cancer patients. An image-based way of pre-surgical lymph node staging consists of using ultrasound images, potentially in combination with other imaging modalities, such as MR.
The ultrasound images are acquired using a hand-held device. 2D images are selected by the operator and saved. Usually, additional markings or annotations, e.g. the long axis and the short axis of the lymph node, are placed by the operator and stored along with the images.
Also, there is a clear trend towards the use of computer-aided detection and diagnosis (CAD) systems in clinical practice. Both for the purpose of computer-aided detection and manual evaluation, the high level of operator dependence on the image acquisition of ultrasound images poses a problem.